Cabinet knob



FIG. 1 is a perspective view of a cabinet knob showing my new design;

FIG. 2 is a side elevational view thereof;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a bottom plan view thereof.

Any dashed lines depict environment and are not part of the claimed design. 

The ornamental design for a cabinet knob, as shown and described. 